Electronic consumer devices become more and more powerful, smaller and faster. This is particularly true for handheld devices like smart phones, which have become immensely popular thanks to their vast functionality combined with their relatively small size. The performance of such devices relies on high clock speeds and small integrated circuit modules.
Prerequisite for high clock speed is high signal speed which creates electromagnetic emissions throughout the electromagnetic spectrum. Such emissions need to be shielded, particularly when the circuits (active components) are positioned very close to each other.
High signal strength and electromagnetic emissions likely result in interference with the operation of the electronic component. This phenomenon is sometimes called electromagnetic interference (EMI) or crosstalk. Shielding is widely used to avoid such interference.
Many component types in electronic devices require such shielding. For example, sub-modules making up the module may need to be shielded from EMI transmissions.
Various methods are known for magnetic or electrical EMI shielding of active components. This is currently predominantly done by metallic cans. However, this technique increases the space requirements, which is detrimental to the trend of miniaturization.
U.S. Pat. No. 8,062,930 B1 addresses the need to reduce space requirements of the can for shielding. Described as a manufacturing process of a submodule having an electromagnetic shield. Initially, a meta-module having circuitry for two or more sub-modules is formed. An overmold body is placed over the circuitry for all of the sub-modules. The overmold body of the metamodule is sub-diced to expose a metallic layer grid around each of the submodules. Next, an electromagnetic shield is applied to the exterior surface of the overmold body of each of the sub-modules and in contact with the metallic layer grid. The meta-module is then singulated to form modules having two or more sub-modules.
An important requirement for those metallized packaged active components is that the I/O (electrical input/output) side of the package is protected from additional metallization as this would lead to shorting of the I/Os.
A related application is the thermal management or dissipation of heat created by active components using a conformal, single-sided metallized layer. Undissipated heat, which is related to the electrical power consumption of the active components can build up to high temperatures (exceeding 150° C.), ultimately deteriorating or destroying the functionality of the active component or chip. Similar as in the EMI shielding application the I/O side has to be protected from additional metallization to prevent shorting of the I/Os.
Thus, there is a need for conformal, single-sided shielding processes capable of effectively and selectively shielding small scale devices and which do not significantly add to the size of the electronic components.